1. Field of the Invention
This invention relates to a synthetic resin composition suitable for use on a cloth for a carpet or a facing material for a seat of a vehicle, or an inner cloth for a door, and also relates to an interior material with a layer coated with the synthetic resin composition.
2. Description of the Related Art
Usually, a synthetic resin composition is laminated on a fiber material for a vehicle. The above synthetic resin composition contains functional materials to do various functions. For example, to remove an odor efficiently, the synthetic resin composition is composed of a latex comprising a resin or a rubber and a filler comprising a hydrated magnesium silicate based clay mineral and activated carbon, which are dispersed into an aqueous medium by a surfactant. The synthetic resin composition is applied to an interior material for a vehicle, thereby removing an odor in the vehicle. This is described in Japanese Laid-Open Patent Publication No. 145864/1990. The synthetic resin composition demonstrates good deodorization for various kinds of odors due to the adsorptivity of a hydrated magnesium silicate based clay mineral and activated carbon. Furthermore, the synthetic resin composition also exhibits the antistatic function by using activated carbon and a cloth, both of which have the electric conductivity.
As for an interior material for a vehicle in which a backing material is laminated on a rear face of the fiber material, a synthetic resin latex is used as the backing material. An inorganic flame retardant and an organic flame retardant are also used with the synthetic resin latex to perform flame retardation. For example, in a synthetic resin composition for an interior material of a vehicle, tetrabromobisphenol A and antimony trioxide are added to a synthetic resin latex for flame retardation.
However, a conventional synthetic resin composition uses only a high molecular weight compound having the weight-average molecular weight of at least 10000 as a dispersant, thereby increasing the viscosity. When the content of a solid material such as a resin or a filler is high, the viscosity is extremely increased. Therefore, the synthetic resin composition industrially usable contains at most 25% of a solid material.
A solid material (hereinafter referred to as a non-volatile matter because a solid material remains after the volatilization) in the synthetic resin composition largely influences the productivity and coating processability (workability) during the coating process and the drying process. In a conventional way, a non-volatile matter is a little and the drying time is long, thereby requiring a high cost and decreasing the productivity and the processability.
As above described, to increase the productivity and processability, it is desirable to increase the amount of a non-volatile matter in the synthetic resin composition.
When an organic flame retardant such as tetrabromobisphenol A and an inorganic flame retardant such as antimony trioxide or antimony pentoxide are used with a filler such as activated carbon or a hydrated magnesium silicate based clay mineral, flame retardation of an interior material in which the synthetic resin composition is used as a backing material improves, but the deodorization deteriorates.
When an acrylic resin in which the glass-transition temperature is not more than -20.degree. C. is used for a ceiling material for a vehicle, it is difficult to form the ceiling material due to a soft resin layer. When an acrylic resin in which the glass-transition temperature is not less than +20.degree. C. is used, it is also difficult to form the ceiling material due to a hard resin layer.
The use of acrylic resin in which the glass-transition temperature is not less than 0.degree. C. on a facing material for a seat results in hard texture and poor seat finish. The use of acrylic resin in which the glass-transition temperature is not more than -55.degree. C. results in poor bonding to the facing material.
As for a rubber latex which is used as a main component of the synthetic resin composition, a layer formed of such latex has poor heat resistance and poor light fastness. So when the layer is exposed to heat or sunlight, it deteriorates with the lapse of time, resulting in poor texture, poor bonding strength to a cloth and peeling off of the layer. Therefore, this material is not suitable for use at parts much influenced by heat and light. The addition of a benzotriazole compound and a benzophenone compound to the synthetic resin composition improves light fastness but not heat resistance. A stabilizer which improves heat resistance will not sufficiently improve light fastness. In order to satisfy both heat resistance and light fastness, an expensive light-stabilizer and an expensive heat-stabilizer have to be used, which causes problems such as selection of proper amounts and high cost.
A backing material comprising the compositions described in Japanese Laid-Open Patent Publication No. 145864/1990 contains only 20% of a non-volatile matter. To form a backing layer which has a bubbling open cell, a thin bubbling backing layer is formed and then a further backing layer is formed thereon repeatedly. So the workability is extremely bad. In this method in which one backing layer having a bubbling open cell is laminated on another backing layer also having a bubbling open cell, a backing material is apt to enter into a cell of the backing layer formed previously. So the deodorization doesn't improve to the extent that is expected.